by Richard@DecisionSkills » Fri Feb 01, 2019 3:41 pm
Potential causes:
-1- Head injury
-2- Psychological trauma and/or psychosomatic
-3- Cognitive decline, usually age related
-4- Chemical imbalance (prescriptions or other substances)
Based on the video I’m going to guess -2-, some sort of stress induced trauma. If this was the case, you would have seen a rather sudden change. He would have been functioning fine and then he begins to act as in the video.
If the change was not sudden, if the change was gradual, then you are probably looking at something similar to the psychological/neurological development of cases like schizophrenia or paranoia.
Hope this helps.
Disclaimer: my background is educational psychology, not clinical psychology.